Stanton is under team control through the 2016 season. Though he has been the subject of trade rumors in the past, it was reported in August that the Marlins will try to sign Stanton to a long-term contract this offseason, and the team now says it will hold on to him at least through the 2015 season.

The team's most expensive deal to date was a six-year, $106 million contract given to shortstop Jose Reyes before the 2012 season. Stanton's value on the open market would likely far exceed that, and he could become the recipient of baseball's first $300 million contract, according to Nightengale.

Stanton has said that he'd be open to re-signing with Miami but only if the team shows a commitment to winning. This season, the Marlins could finish near .500 for the first time since 2010. Miami entered Wednesday at 71-72, 3.5 games behind the second National League Wild Card.

"There has to be some progression moving forward,'' says Stanton. "You can't be just OK hanging around with the big boys. We have to turn it around and become one of the big boys.''

Stanton, 24, is hitting .288 with a .951 OPS, 37 home runs and 105 RBI this season. He tied the Marlins' franchise record for home runs on Monday, hitting his 154th against the Milwaukee Brewers.

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